The invention relates to a method for masking at least a part of a surface to be treated wherein an element that is resistant to surface treatment operations is removably applied to said part of said surface and is removed after finishing said treatment. The invention also relates to a masking means, wherein said masking means is formed by a removable element which is resistant to surface treatments.
Such a masking method and masking means is known from the use of a masking tape, or from the use of a grooved panel of plastic foam as described in the European patent application No. 0207720. These known methods are for example applied in priming and painting of vehicle coachwork, in particular automobile coachwork, or in refinishing work, sandblasting or other surface treatments. In order to prevent paint or other substances to be applied on a surface to be treated from penetrating or covering at least a part of the surface to be treated, that part is masked by using an element that is resistant to surface treatment operations. The element is resistant to surface treatments operations and masks the surface during the treatment and is removed following the treatment.
A drawback of the grooved plastic foam panel is that, due to its panel shape, it is primarily appropriate for masking a planar surface. In particular for surface treatment operation on the body of a vehicle it is not enough to mask only the planar surfaces, since the vehicle body shows a lot of irregularities. Those irregularities usually masked with protection paper and/or masking tape which is a time-consuming operation, because it has to be performed very carefully. Also these known masking methods do not always result in a satisfactory surface treatment. The dust left in the openings can cause contamination of the treated surface. Turbulences can occur around those openings or edges causing an uneven application of the substance to be applied on the surface to be treated.
An object of the invention is to mitigate the above mentioned drawbacks.
According to the present invention a compressible cushion is applied as said element on at least a portion of an irregularity in said surface wherein said cushion is adaptable to said portion of said irregularity on which it is applied.
Due to the fact that the masking element is formed by a compressible cushion, it is no longer necessary to use protection paper nor to apply several masking tape layers in order to mask an irregularity, thus providing a substantial time saving. The compressible cushion adapts itself for filling or covering surface irregularities such as openings or edges. Thus the cushion prevents the formation of turbulences and so the contamination by dust originating from the openings, and enables an adequate masking of the irregularities.
The gist of the present invention is to use an adaptable compressible cushion as masking element in order to mask irregularities. Due to the fact that the cushion is adaptable to the irregularity it takes the exact shape of the irregularity thus providing an excellent masking.
A masking means according to the invention is characterized in that said element is a compressible cushion which is adaptable to the irregularity to which it is applied.
Masking means having the shape of a particular irregularity are known and are for example described in the European patent application No. 0263637. However the difference between a masking means according to the present invention and the masking means according to the latter patent application is that the masking means according to EPA 0269 637 have a particular preformed shape which is on beforehand completely adapted to the irregularity and can thus only be used for masking an irregularity of that particular shape. The masking means according to the present invention is not on beforehand adapted to a particular irregularity but adapts itself to the irregularity to which it is applied. The masking means according to the present invention is thus universally applicable to many kinds of irregularities while the masking means according to EPA 2263637 is not universally applicable.
One should not confuse a masking gasket with a conventional sealing gasket. Indeed, in automobiles it is well known to apply a sealing gasket on the innerlip of a door, hood or a trunk, in the frame of the door or in the other openings which prevents inter alia water and noise from penetrating inside the vehicle. Those sealing gaskets are applied by the manufacturer of the car at a well-defined place and are generally manufactured for each particular automobile model. Those sealing gaskets are quasi-permanently fixed in place. On the other hand, a masking gasket according to the invention only serves for masking, as its name indicates, and not for permanent sealing purposes.
The use of a thermoplastic foam for masking purposes is described in the U.S. Pat. No. 4,714,633. That patent describes the use of an expending and shrinking thermoplastic foam member that contains a cavity. During the surface treatment operation or when the member is heated afterwards, the member according to the U.S. patent will change its form in order to be separated in a natural way of the article on which it has been fixed. On the other hand, the masking means of the invention resists surface treatment operation, i.e. its original configuration will not modify under influence of the surface treatment, unlike the member described in the patent. Contrary to the masking means according to that patent, the masking means according to the invention need not include a cavity which enables a separation operation. The member according to the cited U.S. patent is clearly used in surface treatment operations where its extending and shrinking properties are essential, while the masking means according to the invention is applied in surface treatment operations where its resistance to the treatment plays an important role.
The invention thus provides a non-evident application of a masking means. Indeed, the idea of using a cushion is not evident with respect to the well known use of masking tapes. Several solutions such as pre-treatment of surfaces (see for example the Japanese patent applications 85021787 or 81211929 have already been tested out in order to reduce secondary effects due to the masking during surface treatment operations. The use of a masking means according to the present invention not only enables a substantial time saving but also a quality improvement without use of pre-treatment operations or the like.
A first preferred embodiment of a masking means according to the invention is characterized in that said cushion is an elongated cushion. The elongated cushion offers the advantage that it can be applied in one piece over the whole length of the irregularity to be masked, thus avoiding connection parts which coul cause turbulences having a negative influence on the achievement quality.
Preferably that said cushion has substantially the same cross section over its whole length. This enables a uniform masking.
A first preferred embodiment of a masking method according to the invention is characterized in that said cushion is applied to an elongated irregularity. Elongated irregularities are usual in vehicles. The cushion according to the invention enables an excellent masking of such irregularities in vehicles.
In a second preferred embodiment of a method according to the invention said cushion is positionably adhered on said part of said irregularity. This enables accurate positioning of the cushion when it has incorrectly been applied.
The invention also relates to a device for applying the masking means according to the invention. The device according to the invention is characterized in that it comprises a drum for unwinding said cushion.
In another preferred embodiment a method according to the invention is characterized in that said cushion is formed by applying to said part of said irregularity a polymerizing foam comprising at least a reactive substance. That method is for example applied for masking parts which are difficult to access and thus provides an easy application of the foam on the irregularity to be masked.
A second preferred embodiment of a masking means according to the invention is characterized in that said masking means comprise an elastic foam cushion which is provided with a pressure sensitive adhesive layer, which covers at least a part of said cushion. The cushion can thus easily be applied on the irregularity by simply adhering the cushion thereon.
Preferably said cushion is hollow. this enables saving of material and also gives more flexibility to the cushion.
Preferably said cushion is wound in a coil. This offers an adequate packing for the masking means.